TY - JOUR
T1 - Global Reach 2018
T2 - sympathetic neural and hemodynamic responses to submaximal exercise in Andeans with and without chronic mountain sickness
AU - Hansen, Alexander B.
AU - Amin, Sachin B.
AU - Hofstatter, Florian
AU - Mugele, Hendrik
AU - Simpson, Lydia L.
AU - Gasho, Christopher
AU - Dawkins, Tony G.
AU - Tymko, Michael M.
AU - Ainslie, Philip N.
AU - Villafuerte, Francisco C.
AU - Hearon, Christopher M.
AU - Lawley, Justin S.
AU - Moralez, Gilbert
N1 - Publisher Copyright:
© 2022 American Physiological Society. All rights reserved.
PY - 2022/5
Y1 - 2022/5
N2 - Andeans with chronic mountain sickness (CMS) and polycythemia have similar maximal oxygen uptakes to healthy Andeans. Therefore, this study aimed to explore potential adaptations in convective oxygen transport, with a specific focus on sympathetically mediated vasoconstriction of nonactive skeletal muscle. In Andeans with (CMS , n = 7) and without (CMS+, n = 9) CMS, we measured components of convective oxygen delivery, hemodynamic (arterial blood pressure via intra-arterial catheter), and autonomic responses [muscle sympathetic nerve activity (MSNA)] at rest and during steady-state submaximal cycling exercise [30% and 60% peak power output (PPO) for 5 min each]. Cycling caused similar increases in heart rate, cardiac output, and oxygen delivery at both workloads between both Andean groups. However, at 60% PPO, CMS had a blunted reduction in Dtotal peripheral resistance (CMS+, -10.7 ± 3.8 vs. CMS , -4.9 ± 4.1 mmHg L-1 min-1; P = 0.012; d = 1.5) that coincided with a greater Dforearm vasoconstriction (CMS+, -0.2 ± 0.6 vs. CMS , 1.5 ± 1.3 mmHg mL-1 min-1; P = 0.008; d = 1.7) and a rise in Ddiastolic blood pressure (CMS+, 14.2 ± 7.2 vs. CMS , 21.6 ± 4.2 mmHg; P = 0.023; d = 1.2) compared with CMS+. Interestingly, although MSNA burst frequency did not change at 30% or 60% of PPO in either group, at 60% Dburst incidence was attenuated in CMS (P = 0.028; d = 1.4). These findings indicate that in Andeans with polycythemia, light intensity exercise elicited similar cardiovascular and autonomic responses compared with CMS+. Furthermore, convective oxygen delivery is maintained during moderateintensity exercise despite higher peripheral resistance. In addition, the elevated peripheral resistance during exercise was not mediated by greater sympathetic neural outflow, thus other neural and/or nonneural factors are perhaps involved.
AB - Andeans with chronic mountain sickness (CMS) and polycythemia have similar maximal oxygen uptakes to healthy Andeans. Therefore, this study aimed to explore potential adaptations in convective oxygen transport, with a specific focus on sympathetically mediated vasoconstriction of nonactive skeletal muscle. In Andeans with (CMS , n = 7) and without (CMS+, n = 9) CMS, we measured components of convective oxygen delivery, hemodynamic (arterial blood pressure via intra-arterial catheter), and autonomic responses [muscle sympathetic nerve activity (MSNA)] at rest and during steady-state submaximal cycling exercise [30% and 60% peak power output (PPO) for 5 min each]. Cycling caused similar increases in heart rate, cardiac output, and oxygen delivery at both workloads between both Andean groups. However, at 60% PPO, CMS had a blunted reduction in Dtotal peripheral resistance (CMS+, -10.7 ± 3.8 vs. CMS , -4.9 ± 4.1 mmHg L-1 min-1; P = 0.012; d = 1.5) that coincided with a greater Dforearm vasoconstriction (CMS+, -0.2 ± 0.6 vs. CMS , 1.5 ± 1.3 mmHg mL-1 min-1; P = 0.008; d = 1.7) and a rise in Ddiastolic blood pressure (CMS+, 14.2 ± 7.2 vs. CMS , 21.6 ± 4.2 mmHg; P = 0.023; d = 1.2) compared with CMS+. Interestingly, although MSNA burst frequency did not change at 30% or 60% of PPO in either group, at 60% Dburst incidence was attenuated in CMS (P = 0.028; d = 1.4). These findings indicate that in Andeans with polycythemia, light intensity exercise elicited similar cardiovascular and autonomic responses compared with CMS+. Furthermore, convective oxygen delivery is maintained during moderateintensity exercise despite higher peripheral resistance. In addition, the elevated peripheral resistance during exercise was not mediated by greater sympathetic neural outflow, thus other neural and/or nonneural factors are perhaps involved.
KW - autonomic function
KW - chronic mountain sickness
KW - convective oxygen delivery
KW - exercise hemodynamics
KW - muscle sympathetic nerve activity
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U2 - 10.1152/ajpheart.00555.2021
DO - 10.1152/ajpheart.00555.2021
M3 - Article
C2 - 35333117
AN - SCOPUS:85128489435
SN - 0363-6135
VL - 322
SP - H844-H856
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
IS - 5
ER -